Atrial appendage remodeling device and method

ABSTRACT

The invention describes a method of treating a patient&#39;s left atrial appendage through the pericardial space. The process takes place through the pericardial space from an access point outside the pericardium or pericardial space.

FIELD OF THE INVENTION

[0001] The present invention relates generally to devices and techniquesfor remodeling the atrial appendage of a mammal. The process takes placethrough the pericardial space from an access point outside thepericardium or pericardial space.

BRIEF DESCRIPTION OF THE PRIOR ART

[0002] The atrial appendage is an anatomic feature of the left atrium ofthe human heart. It is widely believed that atrial fibrillation resultsin a pooling of blood in the atrial appendage which results in clots.

[0003] The surgical removal of the atrial appendage through a limitedthoracotomy has been proposed by Johnson in U.S. Pat. No. 5,306,234.However, the surgical removal of the appendage remains problematic sincethe surgical intervention occurs under general anesthesia and isconsidered major surgery. It should also be realized that even atransluminal minimally invasive approach from inside the heart isproblematic since such an approach requires an implantable closuredevice and has the risk of acute stroke. Typically any closure deviceleft in contact with the interior of the heart is potentially athromobogenic surface.

[0004] For these reasons among others there is a continuing need toimprove techniques for occluding or removing the left atrial appendage.

SUMMARY

[0005] In contrast to the prior art, the present invention teachesdevices and methods of using the devices to remodel the atrial appendagefrom locations outside the heart but within the pericardial space. Inuse, the pericardial space is accessed via the chest wall below the ribcage and an endoscope is inserted. It is preferred to perform theprocess steps under visual guidance although robotic and other locationtechnologies may be used in the alternative. The preferred treatment forthe appendage is “wet cautery” where the size and therefore the volumeof the appendage is reduced. An alternate preferred device cuts andcauterizes while removing the appendage. Other surgical techniques areuseful as well including conventional electrosurgery and cautery andconventional suture and staple techniques. In all instances the volumeof the appendage is reduced and in some approaches tissue is removed aswell.

BRIEF DESCRIPTION OF THE DRAWINGS

[0006] The invention is illustrated in the figures where like referencenumeral represent identical structure throughout the several viewswherein:

[0007]FIG. 1 is a schematic diagram of the patient's chest cavity;

[0008]FIG. 2 is a schematic diagram of pericardial access process anddevice;

[0009]FIG. 3 is a schematic diagram of pericardial space visualizationprocess and device;

[0010]FIG. 4 is a schematic diagram of pericardial space electrocauteryprocess and device;

[0011]FIG. 5 is a schematic diagram of an electrocautery process anddevice;

[0012]FIG. 6 is a schematic diagram of an electrocautery process anddevice;

[0013]FIG. 7 is a schematic diagram of an endoscopic suture placementprocess; and

[0014]FIG. 8 is a schematic diagram of an endoscopic staple placementprocess.

DETAILED DESCRIPTION

[0015]FIG. 1 shows the patients heart 10 located within the patient'schest cavity 12. The ribs 14 and skin 16 show the boundary of the chestcavity 12. The left atrial appendage (LAA) 18 is exaggerated in size tofacilitate the description of the invention. The heart 10 chambers liewithin the so-called pericardium 20, which is shown in an exaggeratedscale. The pericardium 20 is a bag like structure that surrounds theheart. It is attached to the great vessels at the “top” of the heart andit completely encircles the ventricles and the atrium of the heart. Thepericardium 20 provides a low friction surface surrounding the heartthat permits motion of the heart. In essence the pericardium allows theheart to “beat” without disturbing other near-by organs.

[0016] The processes of the invention permit the pericardium to remain“intact”. Although several opening to the pericardial space areillustrated it is emphasized that the smaller the number of “holes” inthe pericardium are preferred.

[0017]FIG. 2 shows initial access to the pericardial space though theuse of a pericardial access device 22, which is described in more detailin U.S. Pat. No. 5,827,216 among others. This patent is incorporated byreference herein and the commercially available device is sold under thetrademark “Perducer”. The Perducer is preferred but alternate devicessuch as that taught by U.S. Pat. No. 5,931,810 could be freelysubstituted for the Perducer device. If multiple access points arerequired for a particular patient the two devices may be used together.

[0018] The preferred device 22 has an aperture at its distal end 24 thatallows aspiration of the pericardium 20 into the device. An illustrativesource of vacuum is shown as the physician operated syringe 26. Theaspirated tissue drawn into the device 22 can be pierced by the needle28. The needle 28 can be translated toward the aspirated tissue bypushing on the proximal end of the needle 28.

[0019] A guidewire 30 can next be inserted through the lumen of theneedle 28. With the guidewire in the pericardial space, the physiciancan withdraw the needle and use the guidewire to insert a catheter orother device. The access procedure described may be repeated to providefor multiple access sites or locations into the pericardial space.Although the device shown is preferred it should be recognized thatother devices may be used as well.

[0020]FIG. 3 shows two access sites labeled 50 and 52 respectively. Aguide catheter 40 has been introduced into the pericardial space 42.This access site or port permits access by the endoscope 46 whichincludes a camera 48 and a display system 52. Together these devicesprovide a visualization system allows visual navigation and manipulationof additional surgical tools in the pericardium 20. Although thisvisualization system is not seen in the remaining drawings its useshould be presumed and the deletion from the figure is done to clarifythe remaining drawings. It should be noted that most conventionalendoscopes in use today have laparoscopic tool access ports built intothe device and many steps of the invention can be carried out trough thescope rather than through a separate access site. However, it isexpected that a typical atrial appendage reduction would require twosites, with one devoted to the introduction of a endoscope.

[0021]FIG. 4 shows a snare like electrocautery tool 60 introduced intothe pericardial space 42. The distal loop 64 has been navigated visuallyto “lasso” the atrial appendage. In the device seen in FIG. 4, one endof the snare loop 64 is attached to a tubular body 63 while the otherend is carried through the lumen of the tubular body 63 and attached toa sliding handle 15. A fixed handle 17 is attached to the tubular body63. Traction applied to the snare loop 64 by moving the sliding handlerelative to the fixed handle 17 captures the appendage 18. Theapplication of electrical energy (RF) from the electrocautery unit 70can either remove or close the atrial appendage. It is important to notethat this closure process may be essentially bloodless and may beperformed under direct visualization through the endoscope (FIG. 3).This process is an example of “dry” cautery as opposed to “wet” cauterydescribed in connection with FIG. 6. Although the snare like device ispreferred there are several commercially available products that canalso be used for this step including the loop excision electrodes soldby ValleyLab of Colorado. In general, any specific surgeon may prefer touse other familiar tools for the process. Typically, the electrosurgeryunit 70 will be connected between the loop 64 and a patient grounddepicted as 71. The physician may activate the hand or foot switch 73 todissect the appendage.

[0022]FIG. 5 shows the snare loop 64 isolating the atrial appendage 18prior to the applicant of electrical energy. In the figure the physicianmy grasp an insulator handle and the connection 19 may not be attachedto the generator 70 until after the lasso procedure has beenaccomplished. Although the loop electrocautery device is preferred itshould be noted that the conventional unipolar or bipolar cauteryscissors such as those illustrated as device 13 may be used to cut offthe appendage.

[0023]FIG. 6 shows the use of “wet” electrocautery to “reduce” theatrial appendage. In this procedure the electrical catheter 80 isirrigated by a fluid flow of saline or other conductive fluid 81. Thiswet electrode applies the energy over a wider surface area as aconsequence heat is supplied preferentially to the LAA. It is expectedthat the application of heat will cause the appendage to reduce in sizesubstantially. Fluid assisted electrocautery is known from U.S. Pat. No.6,063,081 among others.

[0024]FIG. 7 shows an alternate method of closing off the atrialappendage. In this situation a suture 90 has been formed into a loop 92and passed over the atrial appendage. A laparoscopic knot pusher 94 ispassed down one leg of the suture 90 to place and tighten a knot formedin the suture. The use of a suture may be preferred given the size andshape of the appendage 18.

[0025]FIG. 8 illustrates an alternate closure device and process. Inthis figure a laparoscopic stapler is used to place one or more staplesto close off the atrial appendage. In the figure the tool 98 has beenused to place one staple seen as staple 97 closing off the appendage.

What is claimed is:
 1. A method for treating the atria appendagecomprising: entering the chest cavity with a surgical instrumentcreating a surgical opening; introducing a pericardial access devicethrough said opening; entering the pericardial space between thepericardium and the heart; navigating an electrosurgery device to theatrial appendage; activating the electrosurgical device to remodel theatrial appendage.
 2. The method of claim 2 wherein said navigating stepis carried out under visual guidance through the endoscopic system. 3.The method of claim 1 wherein said electrosurgical device is a unipolarelectrocautery scissors.
 4. The method of claim 1 wherein saidelectrocautery device is a bipolar electrocautery scissors.
 5. Themethod of claim 1 wherein said electrocautery device is a snare loop. 6.The method of claim 1 wherein said electrocautery device includes atleast one saline electrode.
 7. The method of shrinking the atrialappendage comprising the steps: entering the chest cavity with asurgical instrument creating a surgical opening; introducing apericardial access device through said opening of the type having anextended catheter body with an aspiration lumen for connecting to thepericardium; entering the pericardial space between the pericardium andthe heart; navigating an electrosurgery device of the type having ateast one saline electrode, to the atrial appendage; activating theelectrosurgical device while irrigating the artrial appendage withsaline from the electrosurgery device, to remodel the atrial appendage.9. A method for treating the atrial appendage comprising: entering thechest cavity with a surgical instrument creating a surgical opening;introducing a pericardial access device through said opening; enteringthe pericardial space between the pericardium and the heart; navigatingan endoscopic stapling device to the atrial appendage; activating thestapling device to remodel the atrial appendage by closing off a portionof said atrial appendage.
 10. An electrosurgery device for cuttingtissue comprising: an elongate tubular body; a fixed handle attached tosaid tubular body; a sliding handle adapted to slide along said tubularbody and located proximate said fixed handle; a snare having a first endconnected to said tubular body and a second end attached to said movablehandle, whereby motion of said movable handle manipulates the snare.